Ultrastructural study of early stage of calcification in herpes simplex encephalitis.

A case of herpes simplex encephalitis was investigated at the ultrastructural level. Herpes simplex virions were observed, both in nuclei and perikarya of degenerated cells in the cerebrum. Needle-shaped mineralized precipitates were also present in the disintegrated cells. These mineralized depositions were confined to mitochondria. This finding suggests that mitochondria serve as initial nidus of calcification in herpes simplex encephalitis.